I came through for ya'll here it is pt. 1 of 2 videos of making DIY live
List of Appropriate Aggregates
Sand - Sand makes cement stronger, so is something you want to add to your cement. You may also find that sand is a great casting medium and that you can get crazy shapes with damp sand. Any "clean" sand will work -- look for darker grains which could indicate heavy metals and avoid these sands. Whatever you choose, keep in mind that the smaller the grain size, the less obvious it is on the rock, but for sand for use in the cement, you want a larger particle size, if possible.
Caribbean/aragonite is "best" for adding to the mud, but very hard to find at a reasonable price.
Play Sand is generally fine to use - most play sands will be made of quartz and so basically inert.
Limestone Sand/Pulverized Limestone has gotten good results as a DSB, so should also work and can be found at some Big Box Stores like select Home Despot's.
Glass Sand is a new product on the market that is made from recycled glass - this would also be an excellent choice and might encourage quicker coralline growth.
Calcium Carbonate for "Feed Mixing" (AKA Aglime, Chicken Grit, Scratch Sand), comes in a range of textures and grain size -- from sand to gravel like CC. Most real feed or farm supply stores will carry it in some form, and for less than $4/ #50, but make sure it is the calcium based stuff and not granite based -- it should have a percentage of calcium printed on the bag -- if not, it might not be the stuff you are looking for.
Dolomite Sand -- Same as Calcium Carbonate, just another name (and slight chemical variation) and is just fine to use - you might find it as "Aglime" at the farm supply store.
Sand Blasting Sand can also be used (and works really well as casting sand) and is sugar fine, look for "Unimin" Brand, or any that says it can be used for filtration -- this will be 99% pure Industrial Quartz.
Crushed Coral - AKA "CC". Makes nice, realistic rock with a high over-all calcium content, but it is expensive.
Crushed Oyster Shell - AKA "OS". Any shell will work, but OS is very cheap at feed stores.
Perlite -- has a pore structure similar to CC, but much, much cheaper -- great for making light weight rock. It is basically inert, puffed glass. Make sure that the perlite you choose does not have any fertilizers added to it -- most do not, but a couple do.
Salt - Many thanks to Travis L. Stevens for figuring this out! The salt of choice is "Solar Salt Crystals", typically found as a Water Softener Salt. 99% pure salt. Get the coarsest crystals you can find. Solar Cube can be used, but is sort of chunky - makes nice holes though. Boiling the "cubes" rounds off the edges and makes nicer holes. Solar Pellets can also be used, same as Cubes. Look at your grocery stores or wally-worlds if your local hardware doesn't have what you want.
Rock Recipes
Ingredients are measured by volume, not weight!
Travis' Original "Salt Rock" Recipe: 4:1 or 3:1 / Salt:Cement
Improved? "Salt Rock" Recipe: 3:1 or 2:1 / Salt:Cement
Ol' Skool Recipe: 1 to 1.5 : 2 :1 / Cement:CC&OS(mixed -- or use perlite&shell mix):Sand
Ol' Skool + Recipe: 1: 1 to 1.5 : 1.5 :1 / Salt:Cement:CC&OS(mixed -- or use perlite):Sand
I prefer the "Ol Skool" recipe, but I use a variation with perlite. Makes excellent, porous rock. Keep in mind that even though the original "Salt Rock" recipes do not have sand listed, your rock will be much stronger if you replace a portion of the salt with some sand. On the "Original" recipe I'd use 2 sand and 2 salt to 1 cement.
It is highly recommended that you do not make "Salt Rock". Salt is horrible for cement, and over the last 6 months, I've had more and more complaints coming in about failed, crumbling rock, and guess who gets the blame? Even the "inventor" of Salt Rock, Travis L. Stevens has written and said he too, has salt rock breaking up. So my advice, if you want stable rock, is to not use salt in it, or if you just have to even knowing it is bad, then use it sparingly.
Basic Procedure
Mix dry ingredients together first, excepting salt if used - add tiny amounts of water while vigorously mixing the mud. Mud should be sort of "dry" and a little bit crumbly, not wet and squishy -- there is a fine line between the two. A wet mix will not have as many natural voids in it, be less porous, and will also bind to the salt, making salt release more difficult.
If you aren't adding salt, skip this next part.
Once you have reached a slightly wetter mix then you think you need, lightly toss the salt into the mixture, and then mix it very quickly -- the more salt that leeches off the crystals, the more deleterious the results can be, meaning more chances for your rock to be messed up.
Be aware that a "dry mix" may give the illusion for the first week of being more brittle, but after a week or two, it toughens up and is nice and hard